The professors found that the returns from his investment company Berkshire Hathaway, which far outweigh those achieved by any rival that has operated for 30 years or more, were “neither luck nor magic”.

Instead, the success hinged on a clever use of borrowing money – or “leverage” – in order to make large purchases of “cheap, safe, quality stocks”. In addition, they said Mr Buffett’s returns were “more due to stock selection” than any effect on management of the companies he owned.

Effectively, by using a leverage of around 1.6-to-1 – other words investing £1.60 for every £1 of capital held by borrowing money – Mr Buffett amplified the returns from a low-risk portfolio of stable, profitable companies which had fallen out of favour with other investors.

The paper, written by Andrea Frazzini, David Kabiller and Lasse Heje Pedersen for AQR Capital Management, the asset manager, said: “Every investor has a view on how Buffett has done it, but we seek the answer via a thorough empirical analysis in light of some of the latest research on the drivers of returns.”

The academics created a portfolio that aped the way Mr Buffett borrowed to invest and then followed the stock-selection themes he favoured – and achieved similar returns to Berkshire Hathaway.

The authors said: “Buffett’s genius thus appears to be at least partly in recognising early on, implicitly or explicitly, that these factors work, applying leverage without ever having to fire sale, and sticking to his principles.”

Mr Buffett's bravery in sticking to a high-risk, leveraged portfolio through ups and downs – particularly when other investors were retreating from the markets – was crucial, they added.